Electric circuit breaker



Nov. 15, 1949 R. DUPONT ELECTRIC CIRCUIT BREAKER 4g 2 Sheets-Sheet 1Filed March 27, 1947 NOV. 15, 1949 R DUPONT 2,4882 75 ELECTRIC C IRCUITBREAKER Filed March 27, 1947 2 Sheets-Sheet 2 Patented Nov. 15, 1949UNITED STATES PATENT OFFICE ELECTRIC CIRCUIT BREAKER Roland Dupont,Epernay, France Application March 27, 1947, Serial No. 737,467 In FranceApril 11, 1946 7 Claims. 1

The present invention relates to novel improvements in thermalcircuitbreakers for use in electrically heated apparatus and adapted tocut out the current upon reaching a predetermined temperature.

The present invention is used preferably in connection with vulcanizingapparatus but may also be utilised for various other purposes such forinstance as in a fire-alarm device.

An object of the present invention is a thermal circuit-breaker of thetype wherein the electrical connection is ensured by means of a fuse pinor rod completely independent of the electric circuit, the rupture ofwhich pin or rod causes the cutout mechanism to operate, upon reaching apredetermined temperature.

Another object of my invention is to provide a thermal circuit-breakerwith two different resiliently constrained systems, one of these beingvery weak and acting upon the fuse, while the other is much morepowerful and acts upon the contact studs.

This arrangement has several distinct ad vantages:

First, the pressure exerted upon the fuse being very weak, the same isnot subjected to any external force which would cause it to strain or tobe ruptured prematurely. However, the spring force will be quitesuflicient to rupture the fuse when the same upon being heated to thedesired point has lost its mechanical resistance on account of moleculardisintegration.

Secondly, the strain upon the contact studs being strong, the electricalconnection is always at its best; moreover, the disconnection beingbrought into effect by the sliding movement of the movable contact studsupon the fixed studs, the frictional force exerted therethrough willresult in keeping the contact members in the cleanest condition.

Besides, the movable contact studs are slidable upwardly which willcause the arc of rupture to initiate only on an extreme point at eitherthe lower or upper end of the studs.

Thus, there is never any dirt or particles of metal left in the centerof the contact studs, thereby always ensuring the best possibleconnection.

The objects and novel features of this invention will more fully appearfrom the following detailed description wherein like referencecharacters refer to like parts in the several views.

In the drawings:

Figure 1 is a vertical sectio a i w of m 2 thermal-circuit-breakershowing the same as attached to a vulcanizing apparatus,

Figure 2 is a similar section to Figure 1, but showing the first stageof the connecting operation,

Figure 3 is a cross sectional view with the top broken away taken online 3-3 of Figure 4 which shows the device in operating position,

Figure 4 is a plane view of the device in operating position, the lidbeing taken olf, and

Figure 5 is a partial view of a modification.

According to my invention, herein illustrated by way of example asattached to the heating members of a vuloanizing apparatus, the thermalcircuit-breaker is arranged between two sides I and 2 integral with thecover 3 of the Vulcanizing apparatus 4. The whole unit is kept under alid 5.

The cover is provided with two fixed contact studs 6 and 'l, and alsowith two ejecting lugs 8 and 9, a metallic heat-conducting hook Illextending inside the device.

Two superposed transverse axles H and I2 are provided between the sidesI and 2. Pivotally 25 'qmounted upon the axle l l is a movable operatingmember l3, the free end thereof being arranged as a table to receive thefuse l5. The member l3 forks into two branches [6 and I1, each providedwith a flange 18 in its upper part, and with a flange [9 in its lowerpart. Both flanges I8 and I9 are positioned at right angles with memberI3 in a direction towards the center thereof.

The operative member I3 is urged upwardly by means of a double tensionspring 2!] bearing upon the cover 3 and also upon the flange I8.

Also pivotally mounted upon the axle l I by means of its branches 2| and22 is a support 23 wherein a movable stud carrier is slidably engaged;the free ends of branches 2| and 22 opposite the axle are provided withflanges 24 positioned thereupon at right angle and directed towards theinside, so as to form a channel wherein the movable stud carrier iscapable of sliding. Besides, the branches 2| and 22 have projections 25and 26 extending laterally at right angle to a point adjacent tobranches l6 and I! of the operating member [3 in such a manner that saidprojections will be in the way of flanges l8 and I9. The movable studcarrier comprises two plates 21 and 28 held together transversely by aninsulating member 29 and a bar 30, both acting as cross-pieces.

The ends of plates 21 and 28 opposite to the insulating member 29 areconnected by a trans-. ver o bar 3| which extends outwardly on both'sides through openings 32 provided in both branches 2| and 22 of thesupport 23.

A tension spring 33 connects each end of the bar 3| with the right anglelateral extensions 25 and 26 of the branches 2| and 22.

A lever 34 pivoted at its center in a bearing 35 of the insulatingmember 29 is provided at its ends with contact studs 36 and 31 which arespaced apart in a like manner as the fixed contact studs 6 and I.

The axle I2 has one end projecting outwardly from the side 2 and thisextension forms an operating lever 38 fitted with a hand knob 39.

A stirrup-like member 40 is splined, or secured by any suitable means,upon the axle I2 and when the device is not in working position, saidstirrup member bears, through gravity, against the flanges I8 of theoperative member |3. The stirrup 40 is fitted centrally with adownwardly projecting leg 4| extending in the way of the crosspiece bar30.

The device, being at rest, will be operated as follows:

A suitably shaped and calibrated fuse I is engaged through the slot 42of the lid 5. Said fuse falls upon the table I4, in a temporaryposition, between an angle-shaped punched portion 43 and. a practicallV-shaped receiving member 46, having a central aperture.

The knob 39 is pressed, and thereupon, the stirrup 40 presses theflanges I3 of the operative member I3 which is thereby pivotallylowered. Simultaneously, the leg extension 4| of the stirrup 40 urgesaway the cross-piece bar 33 thus moving the movable stud carrier in adirection towards the axle I I, thereby releasing the contact studswhich come into a position opposite the fixed studs 6 and I, but withoutengaging the latter.

Upon reaching this position, the ejecting lugs B and 9 throw away thefuse I5 from its temporary position and the said fuse comes to restwithin the V-shaped receiving member 44 under the nose of the hook Ill(Figure 2).

Upon release of the hand knob 39, two operations are effectedsimultaneously:

1. The tension springs 33 tend to urge back the stud carrier 33 to itsprevious position and the contact studs 36 and El engage the similarcontact members I3 and l; the cross-piece bar 3i] urges the legextension 4| away, and the stirrup 4D is released and urged upwardly;

2. The operative member I3, being released by the stirrip ll) starts apivoting movement which is however limited by the fuse I5 now held fastbetween the V-shaped receiving member 44 and the nose of the hook It!(Figure 3).

It is to be noted that the slight final upwardly directed movement ofthe operative member I3 does not affect the support 23, and thereforethe contact studs 3|; and 31, as the lower flanges I9 of member I3 aredownwardly set off so as to pro vide for a suitable space between thelatter and the lateral extensions 25 and 26 of the support 23.

Upon reaching the selected temperature which was predetermined by thecomposition of the mixed metal constituting the fuse I5, the said fusewill start to disintegrate; the operative member I3 will then initiatean upwardly directed motion due to the softening of the fuse I5, butthis movement does not affect the engagement of the contact members aspreviously explained. On the other hand, upon rupture of the fuse, theoperating member is moved sharply upwards, and the flanges I9 thereofengage the branches 25 and 26 of the support 23 which is thus also urgedupwards, thereby disengaging the contact members 363| from contacts 6-'|respectively.

As shown in the modification illustrated in Figure 5, the hook It may bereplaced by a bimetallic strip 41; when in operating position, the endof the operative member I3 is engaged under the nose of the bimetallicstrip, and upon reaching the predetermined temperature rated in relationwith said bimetallic strip, the deflection of the latter will releasethe member I3. Said member will then move quickly upwards and thedisconnection will thereby take place as previously explained.

Although only two embodiments of the invention have been illustrated anddescribed, it will be readily understood that various changes in theform and relative arrangement of the parts to suit requirements may bemade without exceeding the scope of the invention or departing from itsspirit. It will also be apparent that the invention is not limited foruse with a vulcanizing apparatus, and, for instance, may be utilised inconnection with a fire-alarm or any other device wherein it is suitableto open or close an electric circuit upon reaching a predeterminedselected temperature.

The object of my invention as herein described may also be used as amere electric cut-out system. In this case, the hook in and the fuse I5are to be replaced by any proper hand-operated mechanism whereby theoperating member I3 may be actuated and thus the circuit broken.

I claim:

1. A thermal actuated circuit breaker for use with electrically heatedapparatus comprising a fixed support, an electrical contact memberfixedly mounted upon said support, an operating member pivotallyconnected to said support, resilient means interposed between saidsupport and said operating member tending to pivot said operating memberrelative to said support, a pivotal support, an electrical contactcarrier slidably carried by said pivotal support for movementlongitudinally thereof, electrical contacts mounted on said carrier forengaging said first mentioned fixed contact member, temperatureresponsive means independent of the electrical circuit and capable ofretaining said operating member against the action of said resilientmeans until a preselected temperature is reached, and means, carried bysaid contact carrier, for moving said movable contacts out of engagementupon release of said operating member by said temperature responsivemeans.

2. A thermal actuated circuit breaker for use with electrically heatedapparatus as claimed in claim 1 in which spring means is interposed between said pivotal support and said slidable contact carrier for urgingsaid contact into engagement with said fixed contact member when saidoperating member is in its closed circuit position.

3. A thermal actuated circuit breaker for use with electrically heatedapparatus as claimed in claim 1 in which said resilient means tends tomove said operating member in a direction which will cause the slidabledisengagement of said fixed contact member from said movable contact forpreventing an are from forming between said contacts.

4. A thermal actuated circuit breaker for use with electrically heatedapparatus as claimed in claim 1 comprising a manual controlled actuatedmember pivotally mounted on said support and capable of urging saidoperating member into coupling position with said temperature responsivemember, a leg extension carried by said actuating member for urging atthe same time said slidable contact carrier away from said fixed contactmember.

5. A thermal actuated circuit breaker for use with electrically heatedapparatus as claimed in claim 1 comprising a fusible member, a tablearranged on said operating member to receive said fuse in a temporaryposition when said operating member is in its released position, fixedabutments for throwing said fuse into its working position when saidoperating member is moved against the action of the spring thereof and afixed hook arranged to be in the way of said fuse when the same is inits working position.

6. A thermal actuated circuit breaker for use with electrically heatedapparatus as claimed in claim 1 including means for pivoting saidpivotal support from a position wherein said fixed and movable contactsare opposite to one another to a position wherein said contact membersare not opposite one another and vice versa with said movable contacthaving a sliding disconnecting movement against said fixed contact.

7. A thermal actuated circuit breaker for use with electrically heatedapparatus comprising a fixed support, a pair of electrical contactsfixedly mounted upon said support, an operating member pivotallyconnected to said support, resilient means interposed between saidsupport and said operating member tendin to pivot said operating memberrelative to said support, an electrical contact carrier, electricalcontacts mounted on said carrier for engaging said first mentioned fixedcontacts, a second member pivotally connected to said support andforming a channel having said carrier slideably mounted therein, atemperature responsive member independent of the electrical circuit anddesigned to maintain said first pivotal member against the action ofsaid resilient means until a preselected temperature is reached andmeans through which the pivoting of said first member actuates saidsecond member with suitable play being provided between said pivotingmembers.

ROLAND DUPONT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,091,035 Foster Aug. 24, 19372,416,407 Runke Feb. 25, 1947

